Injection system and process

ABSTRACT

The present invention relates to an injection system for injecting material into a receiving vessel, said injection system comprising: (i) an injection chamber provided with means to connect to the receiving vessel, and (ii) an injection capsule, adapted to fit within the injection chamber, and comprising a reservoir for the material and a valve, said injection system being adapted so that opening of the valve causes material contained within the reservoir to be injected into the receiving vessel by action of a pressure differential between the injection chamber and the receiving vessel. The present invention also relates to a method of injecting material into a receiving vessel using said injection system.

This invention relates to an injection system for injection of amaterial into a receiving vessel, and to a process for injection ofmaterial into said vessel using the injection system.

Catalysts are widely in used in numerous chemical processes atindustrial scale. Novel and/or improved catalysts may be discovered andresearched by many methods known to those skilled in the art.

Catalyst handling and catalyst addition to a reaction apparatus arecommon actions to almost any chemical experiment or process involvingsuch a catalyst. Over recent years the advent of combinatorial methodsin materials science and of high throughput chemistry techniques, and inparticular the growing use of robots and computers to automate catalystand materials preparation and testing, has allowed researchers topotentially test tens to hundreds to thousands or more catalysts andmaterials in parallel. Much effort has gone in to developing preparationand testing apparatus for numerous types of materials and materialproperties (for example U.S. Pat. No. 5,776,359) and, in particular, forchemical reactions of interest (for example see U.S. Pat. No. 5,959,297,U.S. Pat. No. 6,063,633 and U.S. Pat. No. 6,306,658). However as thenumber of experiments it may be possible to run in parallel hasincreased so the bottlenecks in catalyst testing have shifted. Forexample, collecting, handling and storing of experimental data hasbecome an increasingly important area. As a further example, where aresearcher had previously to only make, load and test a few catalysts aday or even in a week, the researcher now has to make a much largernumber of catalysts to perform the tests on. In addition, the scale(i.e. volume of catalyst tested) on which high throughput experimentsare run has generally decreased inversely to the increase in number ofparallel experiments, giving corresponding difficulties in thepreparation of a large number of separate small volumes of material.This problem has been addressed to some extent by the use of variousrobotic techniques and/or other automation to prepare said catalysts.

However, even once the catalyst material is prepared other keybottlenecks include the handling of the catalyst and other materialsthat have been previously prepared and, in particular, the loading ofsaid materials in to reactors. This is particularly so in relation tothe handling and loading of solid materials. We have now found animproved method for injection of materials in to a receiving vessel.

Thus, according to the first aspect of the present invention there isprovided an injection system for injecting material into a receivingvessel, said injection system comprising: i) an injection chamberprovided with means to connect to the receiving vessel, and ii) aninjection capsule, adapted to fit within the injection chamber, andcomprising a reservoir for the material and a valve, said injectionsystem being adapted so that opening of the valve causes materialcontained within the reservoir to be injected into the receiving vesselby action of a pressure differential between the injection chamber andthe receiving vessel.

In operation of the injection system there is a pressure differentialbetween the injection chamber and the receiving vessel in to whichmaterial is desired to be injected, such that the pressure in theinjection chamber is greater than the pressure in the receiving vessel.On opening of the valve in the injection capsule the flow of fluid, forexample pressurised gas, from the injection chamber to the receivingvessel due to this pressure differential causes the material within theinjection capsule to be carried or forced out of the injection capsuleand in to the receiving vessel.

Preferably, the injection system of the present invention may be used toinject material into a receiving vessel which is at greater thanatmospheric pressure.

This injection capsule valve may be any suitable valve. In oneembodiment the injection capsule valve may be any suitable manuallycontrolled valve i.e. the injection capsule valve may be opened manuallyonce the desired pressure differential has been established. In anotherembodiment the injection capsule valve may be electrically actuated,such that the valve will open when suitably triggered.

Preferably, the injection capsule valve may be actuated by the pressuredifferential. In one embodiment an electrically actuated valve mayitself be set to depend on the pressure differential, such that theestablishment of a suitable pressure differential causes the electricalsignal for the valve to be opened. In a preferred embodiment, theinjection capsule valve is directly pressure actuated, such that thevalve is opened under the pressure of the pressure differential itself.Most preferably, the injection capsule valve comprises a plate that isbiased in the closed position when the pressure differential across theplate is substantially zero. For example, the injection capsule valvemay comprise a suitable spring and plate assembly, wherein the plate isheld in a closed position by the spring when there is no pressuredifferential.

The injection system of the present invention is especially suitable fordelivery of material in the solid form, however it will be readilyapparent that the system is equally suitable for injection of materialin other forms, for example in liquid form or in slurry form, or amixture, such as a mixture of a solid and a liquid. Where the materialsare in solid form they may be in any suitable solid form, for example aspellets or as powders of varying particle size. Preferably, the solidmaterial to be injected is substantially dry.

The injection system of the present invention may be sized to deliverany appropriate quantity of material. The present invention is howevermost advantageously used where it is desired to fill receiving vesselswith relatively small quantities of particular materials, whereinconventional material handling may be awkward, difficult and/or complexdue to the small size of the samples to be injected. In particular wheresmall quantities of material are to be injected it is likely to bedesirable to inject substantially all the material in to the receivingvessel without leaving any residual material.

The injection system of the present invention may also be readilyautomated or semi-automated to inject the material into the receivingvessel. For example, the present invention is particularly advantageousfor use with the types of apparatus where use of automation in materialinjection is desirable. Most preferably, the injection system of thepresent invention may comprise a plurality of injection chambersconfigured so as to deliver material to a plurality of receivingvessels, such as 2 or more parallel receiving vessels, preferably morethan 5 parallel receiving vessels, or more than 10 receiving vessels. Inone embodiment the there may be more than 20, such as more than 50 or100 receiving vessels

The injection capsule may be loaded in to the injection chamber andsubsequently removed from the injection chamber by any suitable means.In a preferred embodiment the injection system comprises at least partlyautomated means for manipulation of the injection capsules, such as, forexample, for loading, unloading and/or other handling of the injectioncapsules.

Preferably, the injection capsule manipulation means comprises a roboticarm the lower part of which is no wider than the inner diameter of theinjection chamber. This allows manipulation of the injection capsule bythe robotic arm within the injection chamber.

The robotic arm may manipulate the injection capsule using any suitablemethod. For example, the injection capsule may comprise one or morehandles or hooks which may readily interface with the robotic arm.

In a preferred embodiment, the robotic arm manipulates the injectioncapsule using magnetism. For example, at least part of the injectioncapsule and at least part of the robotic arm may be made of mutuallyattractive magnetic materials. For example, the whole of the injectioncapsule may be magnetic, or only the top of the injection capsule maycomprise magnetic material. In another embodiment, the robotic armcomprises an electromagnet. In this embodiment the robotic arm and theinjection capsule may be separated by turning off the electromagnet.

In another embodiment, the robotic arm comprises two or more sections,at least one of which comprises a magnet or electromagnet and may beindependently retracted, and at least one section which is non-magnetic.Preferably, the robotic arm comprises two sections, one of which is amagnet and one of which is non-magnetic. The non-magnetic section mayhold the injection capsule in position in the injection system whilstthe remainder of the robotic arm, comprising the magnet, retracts. Oncethe magnets are separated by a suitable distance the non-magneticsection can itself retract, leaving the injection capsule in place.

Most preferably, the centre of the robotic arm comprises a central(core) section (plunger) and an outer section, which are independentlyretractable. The plunger is adapted to cover the entrance of thereservoir for the material, for example a plunger which has a base widthwider than the hole at the top of the injection capsule and/or fits theentrance to the reservoir. In a preferred embodiment, the injectioncapsule comprises a frusto-conicular entrance to the reservoir for thematerial, and the plunger is adapted to fit this shape. By covering theentrance to the reservoir the plunger may act to protect the materialwithin the reservoir during manipulation e.g. protect from spillage orcontamination. In addition the frusto-conicular entrance may allowimproved ease of loading of material in to the reservoir. Preferably,this plunger is non-magnetic and may hold the injection capsule inposition in the injection system whilst the remainder of the roboticarm, comprising the magnet or electromagnet retracts. Once the magnetsare separated by a suitable distance the plunger can itself retract.

In a further embodiment the external surface of the injection capsuleand the internal surface of the injection chamber may comprise threads,such that the injection capsule may effectively be screwed in to theinjection chamber. In this case the top of the injection capsule maycomprise a suitable slot that allows the robotic arm to interact andexert a rotational force, for example as with a screwdriver interactingwith a screw or similar.

In a preferred embodiment, wherein the injection system comprises aplurality of injection chambers the loading process may be readilyrepeated to load injection capsules in to other injection chambers asrequired.

Most preferably, the manipulation means also allows injection capsulesto be retrieved from the injection chamber by the robotic arm. Once oneinjection capsule has been removed from the injection chamber a furtherinjection capsule may, if desired, be loaded in to the injection chamberfor injection of further material.

Most preferably, the material to be injected is a catalyst material andthe one or more receiving vessels are a suitable reaction apparatuscomprising one or more reactors. However although the invention willfrom herewith be illustrated by reference with a reaction apparatus andto catalyst materials it will be readily apparent to one skilled in theart that the injection capsule and injection system may also be used toinject other materials in to a reaction apparatus or other receivingvessel. These other materials may include, for example, materials suchas solvents, reactants, promoters, poisons, quench agents, scavengers,support particles and inert solids. In addition, by catalysts, as usedthroughout this invention, it is intended to include reference to anymaterials which may form catalysts or catalytically-active materialsafter injection, such as individual components of a catalyst system.

The injection system may be adapted for any suitable quantity ofmaterial to be injected and for any suitable size of receiving vessel.

As described herein, the present invention is particularly useful whereit is desired to inject a relatively small volume of material,especially, for example, where the receiving vessel is one of aplurality of receiving vessels, such as one of a plurality of reactionvessels (reactors). Preferably, each receiving vessel may have a volumeof 2.5 litres or less, more preferably 1 litre or less. The receivingvessels preferably have a volume of at least 10 ml, and most preferablyhave a volume between 10 ml and 500 ml. However, the invention is alsoapplicable to significantly larger reactors or significantly smallerreactors, such as those with volumes above 5 litres or below 1 ml.

Preferably, the volume of the injection chamber is such that, with theinjection capsule in place, the volume of pressurising fluid in thechamber above the material to be injected is sufficient to ensure cleaninjection of the material in to the receiving vessel. In certainaspects, it may also be preferred that the volume of pressurising gasshould not be too large relative to the receiving vessel volume, sinceif the relative volume is too large the pressurising fluid can causesignificant perturbations in the conditions in the receiving vessel. Forexample, where the receiving vessel is a reaction vessel containing areactant gas and the pressurising gas is an inert gas, such as nitrogen,the use of too large a volume of pressurising gas may cause significantperturbation of reaction conditions and/or reactant dilution wheninjected.

Preferably, especially where it may be desired to avoid or minimisesignificant perturbation of the conditions in the receiving vessel, theinjection chamber is sized to have a capacity of less than 20% of thereactor volume, such as between 10 and 20% of the reactor volume.

Preferably, each injection capsule may deliver a maximum quantity ofcatalyst of up to 1 g, such as up to 500 mg to each reactor. Morepreferably, each injection capsule may deliver a maximum quantity ofcatalyst material of up to 250 mg, such as up to 100 mg to each reactor.

Preferably, each injection capsule may deliver a minimum quantity ofcatalyst of down to 0.1 mg or lower, such as down to 0.25 mg. Morepreferably, the minimum quantity of catalyst may be down to 0.5 mg, suchas a minimum of 1 mg.

The catalyst may be injected essentially pure or undiluted.Alternatively, a mixture of catalyst materials may be injected. Inaddition, the catalyst may also be injected in a “diluted” form. Forexample, for injection of a solid catalyst the catalyst may be injectedwith a further solid material that is inert in the reaction of interest.Suitable inerts will be well-known to those skilled in the art for aparticular reaction. Preferably, the inert particles will have a similarsize to the catalyst particles. In a further preferred embodiment, thecatalyst and inert particles are intimately mixed. The catalyst is mostpreferably injected in diluted form, for example as a mixture with afurther inert material, when only a small quantity of catalyst material,such as 25 mg or less, for example, 15 mg or less or 5 mg or less is tobe injected. This is particularly preferred where the diluted form mayallow easier handling.

Preferably, the injection system for catalyst material also comprises atleast partly automated means for manipulation of the injection capsule,for example, as described herein.

It may also be important to know accurately how much catalyst is beinginjected to the reactor. In a preferred embodiment, the injection systemalso comprises a means to measure the quantity of material beinginjected. In a most preferred embodiment, this may comprise a weighingapparatus or weighing station wherein the injection capsules may beweighed when empty and when full of material.

Where the catalyst or other material to be injected comprises materialin a liquid form, for example as a pure liquid or as a solution, such asan aqueous solution or as a suspension of solids in a solution, then thequantity of material to be delivered may be measured by mass, as above,or may be measured by volume. For example, a known volume of liquid maybe added to the injection capsule using any suitable dispensing system.Preferably, each injection capsule may deliver a maximum volume ofliquid of up to 10 ml, such as up to 5 ml, to each reactor. Morepreferably, each injection capsule may deliver a maximum volume ofliquid of up to 1 ml, such as up to 500 μl to each reactor.

Preferably, each injection capsule may deliver a minimum volume ofliquid of down to 1 μl or lower, such as down to 10 μl. More preferably,the minimum quantity of liquid may be down to 50 μl, such as a minimumof 100 μl.

The injection capsule and injection system of the present invention maybe used with any suitable reaction or catalyst to be studied. Forexample, the reaction may be performed at any pressure, includingatmospheric pressure, or at lower than atmospheric pressure. In apreferred embodiment, the reaction will be one that is operated atgreater than atmospheric pressure, such as above 2 bar, above 5 bar orabove 10 bar, for example, above 30 bar or even above 50 bar. Where thereaction to be performed is to be operated at greater than atmosphericpressure then the catalyst may be injected in to the reactor atatmospheric pressure, in the presence or absence of other materials,such as solvents, for example, and the reactor subsequently pressurised.Most preferably, the injection system of the present invention may beused to inject catalyst in to a reactor that is at greater thanatmospheric pressure. Most preferably, the injection system may be usedto inject the catalyst in to the reactor at, or close to, the desiredreaction pressure. In a further most preferred embodiment, the catalystis injected in to the reactor at, or close to, reaction pressure and at,or close to, reaction temperature. This allows a consistent “start” timefor the reaction to be obtained where this may be important (for examplethe time when the catalyst is injected, or after a suitable inductiontime if required).

A preferred embodiment of the invention will now be illustrated withreference to the figures.

FIG. 1 shows an injection capsule according to one embodiment of thepresent invention. The injection capsule comprises a cylindrical tube,1, of outer diameter a and inner diameter b. At the base of the cylinderis the injection capsule valve, 2, which may comprise a plate, 3.Catalyst or other material may be loaded in to the reservoir, 4, in theinner of the cylindrical tube, 1, supported on the plate, 3. The platewill hold the material within the inner region when it is in the closedposition, for example, when there is no or only is a low pressuredifferential on either side. In the open position the plate isconfigured to allow material past the plate and out of the injectioncapsule. In a preferred embodiment the injection capsule valve uses asuitable spring assembly, such as, for example an assembly similar tothat use in a conventional non-return valve to support the plate. Thespring assembly may be supported on an end cap, 5, which also has acentral hole that lines up with the rest of the injection capsule. In afurther preferred embodiment the end-cap, 5, may be removed to allowcleaning, repair or replacement of the seal/valve assembly.

FIG. 2 shows an injection system according one embodiment of the presentinvention. The injection capsule, 6, sits within the injection chamber,7 of the injection system. The inner diameter, c, of the injectionchamber is fractionally more than the outer diameter, a, of theinjection capsule, so that the injection capsule fits closely, but nottoo tightly within the injection chamber. Beneath the base of theinjection capsule is a further valve, 8. Below this valve is thereceiving vessel. At the top of the injection chamber is a furthervalve, 9. Valves 8 and 9 may individually be manually or automaticallyoperated. The injection chamber is also connected to a tube, 10.

In use, with valve 9 open (and valve 8 closed) the injection capsule iscarefully loaded through the top of and in to the injection chamber. Dueto the nature of the injection system the injection capsule should fitclosely within the injection chamber. Once the injection capsule isloaded valve 9 may then be closed.

The injection chamber may then be pressurised through tube 10.Preferably this may be done using any suitable gas. In one embodimentthis may be a reactant gas for a specific reaction of interest. In apreferred embodiment this may be done with an inert gas, for example,nitrogen or argon.

It is important not to disturb the material in the injection capsuleduring pressurisation. In addition, due to the close fit of theinjection capsule within the injection chamber gas may only slowlypermeate through and pressurise the area below the injection capsulevalve, 2. Therefore it is preferred to pressurise the injection chamberso as to ensure even pressurisation and no disturbance of the material,for example by pressurising slowly. Alternatively the injection capsulemay be provided with a cover or cap which may protect the top of theinjection capsule during pressurisation (and also general handling asdescribed throughout this specification). This cover or cap may beremoved or otherwise opened once the system has been fully pressurised.

In an alternative embodiment the injection chamber may be pressurisedthrough more than one tube. For example, in one embodiment there may beadditional tubes for pressurisation of the injection chamber below theplate, 3, so that this area may be pressurised through a separate tubeattached to the area below the injection capsule valve, such as attachedto valve 8. This area is preferably pressurised at approximately thesame rate as the upper area. Additionally or alternatively there may bemore than one tube attached to the upper area so as to improve thepressurisation of the upper area of the injection chamber. In a furtherembodiment the injection chamber may be pressurised using more than onegas, either as a mixture, sequentially through the same tube, or throughdifferent tubes.

In still another embodiment the injection chamber may be filled andpressurised in whole or in part using a pressurised liquid. For example,this may be desirable where the material is a “sticky” solid. Usingliquid to inject the solid may reduce the amount that is retained withinthe injection capsule.

The injection chamber should be pressurised to a pressure greater thanthe pressure in the receiving vessel below, such as at least 2 barabove, but preferably at least 5 bar above the pressure in the receivingvessel. Most preferably the injection chamber should be pressurised toat least 10 bar greater than the pressure in the receiving vessel.

After the injection chamber has been pressurised, and allowed toequilibrate if required (for example, where a liquid is present and ispressurised with gas some of the gas may dissolve in the liquid) valve 8may be opened to inject the material in to the receiving vessel.

Due to the pressure differential between the injection chamber above theinjection capsule and the receiving vessel below, and further due to theclose fit of the injection capsule in the injection chamber the gasabove the injection capsule will be forced to push through the centre ofthe injection capsule, and will inject any material within the injectioncapsule in to the receiving vessel.

In one embodiment valve 8 may be closed immediately after injection. Inan alternative embodiment further gas or liquid may be used to flushthrough the injection capsule.

In yet another embodiment, once valve 8 is closed the injection capsulemay be removed from the injection chamber. A further injection capsulemay then be loaded if it is required to inject further material, forexample, fresh or additional catalyst, solvent or reactants, or a quenchagent for a reaction.

In a preferred embodiment the injection system comprises a cleaningsystem to clean the injection chamber once the injection capsule hasbeen removed. In one embodiment this may be done using a vacuum, forexample through tube 10 or a similar tube. In another embodiment theinjection chamber may be filled with a suitable solvent liquid, whichmay then be removed, for example by vacuum. In another embodiment anysolvents and/or vacuum means may be introduced using a robotic arm andby opening valve 9, such as a liquid handling robot.

The present invention also provides a process for injecting materials into one or more receiving vessels using an injection system as definedherein, said process comprising: i) providing an injection capsule,containing the material to be injected, within the injection chamber,ii) pressurising the injection chamber to a pressure above that in thereceiving vessel, and iii) opening a valve so that material is injectedin to the receiving vessel.

Preferably the process may also comprise one or more steps in which oneor more materials may be loaded in to the injection capsules and/or maybe weighed within the injection capsules and/or may otherwise bemeasured in to the injection capsules, for example, by liquid volume.

The entire process may, if necessary, be performed in an inertatmosphere, such as in a glove box.

Preferably, the receiving vessel is at greater than atmosphericpressure. The injection chamber may be pressurised to a pressure abovethat in the receiving vessel using an inert gas. Preferably, theinjection chamber is pressurised to a pressure at least 5 bar above thepressure in the receiving vessel.

Preferably, the process of providing an injection capsule in step (i)comprises loading of the injection capsule using a robotic arm the lowerpart of which is no wider than the inner diameter of the injectionchamber. The process for injecting materials may further compriseretrieving the injection capsule from the injection chamber afterinjection of the material in to the receiving vessel, for example, usinga robotic arm the lower part of which is no wider than the innerdiameter of the injection chamber.

Preferably, the receiving vessel is a suitable reaction apparatuscomprising a reactor and the material is selected from catalystmaterials, solvents, reactants, promoters, poisons, quench agents,scavengers, support particles or inert solids, more preferably acatalyst material.

Most preferably, the material is a polymerisation catalyst and thereceiving vessel is a polymerisation reactor containing one or moremonomer reactants.

This process is illustrated below with respect to loading of catalystsin to a reaction apparatus, but it will be readily apparent that thismay equally apply to other materials and receiving vessels.

Where a solid catalyst is to be used an empty injection capsule may bepre-weighed using any suitable weighing process. Although this may bedone manually, it is preferably done automatically using any suitableautomated weighing apparatus. The injection capsule is then loaded witha catalyst material and re-weighed. Again this process may be manual butis preferably at least partly automated, most preferably fullyautomated.

The solid catalyst material may comprise an undiluted or a dilutedcatalyst, for example a solid intimately mixed with an inert of similarparticle size. As long as mixing ratio or concentration of catalyst inthe diluted sample (e.g. g catalyst/g sample) is known the amount ofactual catalyst material loaded may be easily calculated from therespective weights of the loaded and unloaded injection capsule.

After weighing of the solid catalyst a further layer comprising a smallamount of non-catalyst material may preferably be added to the top ofthe injection capsule. This may be any material that is inert in thespecific reaction, but is preferably an inert anti-static material, suchas any suitable salt.

This layer helps to protect the solid catalyst material during handlingand injection.

Where a liquid is used as a catalyst, the liquid weight may becalculated similar to above, or the volume of catalyst may be used.

The injection capsule may then be picked up by a robotic arm, preferablyusing magnetism to hold the injection capsule. The lower part of therobotic arm has a smaller diameter than the inner diameter of theinjection system. Preferably the base of the robotic arm completelycovers the hole at the top of the injection capsule to protect thecatalyst during transport and loading in the injection system.

The injection capsule is carefully lowered in to an injection chamber inthe injection system of the present invention. The robotic arm mayrepeat this process for further injection capsules to be loaded in otherreactors.

The loaded injection chamber(s) may be pressurised, and the catalyst(s)injected as described above.

After the injections the injection capsule(s) may be retrieved from theinjection chamber(s) by reversing the loading process. The robotic armis slowly lowered in to the injection chamber until it contacts theinjection capsule. The robotic arm lifts the injection capsule out ofthe injection chamber.

In a most preferred embodiment, if required, the injection capsule maybe transported to a suitable location for cleaning of the injectioncapsule, for example for washing of the injection capsule.

In a further aspect, the present invention also provides an injectioncapsule for use in the injection system as described herein.

EXAMPLES Experimental

The following examples were performed in a 270 ml autoclave to which isattached an injection system according to the present invention. Theinjection chamber and the autoclave may be isolated from one another viaa valve.

The autoclave and injection chamber were situated directly below a glovebox used for making up the catalyst mixtures. All catalyst handling isperformed under an inert atmosphere.

All gases and reagents used were of polymerisation grade.

Example 1 Injection of Dry Catalyst in Gas Phase Process (Ziegler LLDPE)

0.2 mmol triethylaluminium (TEA) was added to the autoclave at 30° C.which already contained 60 g of pre-dried sodium chloride. The autoclavewas heated to 85° C. and then pressurised to a total pressure of 5.9 barwith a composition of 71.4% v/v ethylene, 17.9% v/v hydrogen and 10.7%v/v hexene (as measured by a mass spectrometer).

20 mg of a supported Ziegler polyethylene catalyst (catalyst A) wasmixed with 980 mg of a solid diluent (TEA treated silica) in thenitrogen glove box and loaded into an injection capsule.

The injection capsule was transferred in to an injection chamber atatmospheric pressure via the use of a magnetised rod comprising anon-magnetic core section (plunger) and a magnetic outer section, whichare independently retractable. The injection chamber was thenpressurised with nitrogen to 10 bar above the autoclave pressure. Thevalve between the autoclave and the injection chamber was then openedallowing the catalyst and TEA treated silica mixture to be injected intothe autoclave. The pressure in the autoclave increased to 7.24 barduring the injection and then the autoclave pressure was controlled atthis increased pressure by addition of further reactant gas compositionas required to maintain this pressure. The test was allowed to proceedfor 60 minutes at constant pressure and composition, and underfluidisation conditions.

The product was removed at the end of the test by venting the reactantgases, cooling the autoclave to 30° C. and opening a valve on the bottomof the autoclave. The autoclave was cleaned for the next test by washingwith 200 ml of heptane. All solid and liquid material from the autoclavewas collected.

After evaporating the heptane the sodium chloride was removed by washingwith water. 10.2 g of LLDPE product was obtained

The injection capsule was removed from the injection chamber by ventingany pressurised gas remaining in the injection chamber and using themagnetic rod to remove the injection capsule. Any residual solidmaterial in the injection chamber was removed by using a vacuum line.

On removal of the autoclave no significant deposits were seen on thewalls below the valve leading into the autoclave.

Example 2 Injection of Dry Catalyst in Gas Phase Process (MetalloceneLLDPE)

The autoclave containing 60 g of pre-dried sodium chloride and at 75° C.was pressurised to a total pressure of 6.5 bar with the composition of99.1% v/v ethylene, 0.3% v/v hydrogen and 0.6% v/v hexene (as measuredby a mass spectrometer).

10 mg of a supported metallocene polyethylene catalyst (catalyst B) wasmixed with 980 mg of a solid diluent (TEA treated silica) in thenitrogen glove box and loaded into an injection capsule. A further 100mg of dried sodium chloride was added on top of this mixture in theinjection capsule to eliminate any problems of static during transfer ofthe injection capsule to the injection chamber.

The injection capsule was transferred in to an injection chamber atatmospheric pressure via the use of a magnetised rod comprising anon-magnetic core section (plunger) and a magnetic outer section, whichare independently retractable. The injection chamber was pressurisedwith nitrogen to 10 bar above the autoclave pressure and the valve tothe autoclave was opened allowing the catalyst and TEA treated silica tobe injected into the autoclave. The pressure in the autoclave increasedto 8.6 bar and the autoclave pressure was then controlled at thisincreased pressure by addition of further reactant gas composition asrequired to maintain this pressure. The test was allowed to proceed for60 minutes at constant pressure and composition, and under fluidisationconditions.

The product was removed at the end of the test by venting the reactantgases, cooling the autoclave to 30° C. and opening a valve on the bottomof the autoclave. The autoclave was cleaned for the next test by washingwith 200 ml of heptane. All solid and liquid material from the autoclavewas collected.

After evaporating the heptane the sodium chloride was removed by washingwith water. 6.4 g of LLDPE product was obtained.

The injection capsule was removed from the injection chamber by ventingthe pressurised gas remaining in the injection chamber and using themagnetic rod to remove the injection capsule. Any residual solidmaterial in the injection chamber was removed by using a vacuum line.

On removal of the autoclave no significant deposits were seen on thewalls of the tubing below the valve leading into the autoclave.

Example 3 Injection of Dry Catalyst in Slurry Phase Process (ZieglerLLDPE in Isobutene Solvent)

12.2 g of dried glass beads (2 mm diameter) was added to the autoclaveto fill up the dead space at the bottom of the autoclave duringreaction. 10 ml of anhydrous pentane was added to the autoclave to fillup the dead volume around the glass beads.

Triethylaluminium (2 mmol) was added to the autoclave followed by 20 mlof hexene and 150 ml of isobutene. The autoclave was heated to 85° C.and then hydrogen was added to 0.62 bar and ethylene added to 7 barabove the pressure of the isobutene/hexene.

14 mg of a supported Ziegler polyethylene catalyst (catalyst C) wasmixed with 980 mg of solid diluent (TEA treated silica) in a nitrogenglove box and loaded into an injection capsule.

The injection capsule was transferred in to an injection chamber atatmospheric pressure via the use of a magnetised rod comprising anon-magnetic core section (plunger) and a magnetic outer section, whichare independently retractable.

The injection chamber was then pressurised with nitrogen to 10 bar abovethe autoclave pressure and the valve to the autoclave was openedallowing the catalyst and TEA treated silica into the autoclave. Thepressure in the autoclave increased and the autoclave pressure was thencontrolled at this increased pressure by addition of further reactantgas composition as required to maintain this pressure. The test wasallowed to proceed for 35 minutes at constant pressure and composition.

The product was removed at the end of the test by venting the reactantgases and isobutane, cooling to 30° C. and opening a valve on the bottomof the autoclave. The autoclave was cleaned for the next test by washingwith 200 ml of heptane. All solid and liquid material from the autoclavewas collected.

On evaporating the heptane 13.5 g of LLDPE product was obtained. Theinjection capsule was removed from the injection chamber by venting thepressurised gas remaining in the injection chamber and using themagnetic rod to remove the injection capsule. Any residual solidmaterial in the injection chamber was removed by using a vacuum line.

On removal of the autoclave no significant deposits were seen on thewalls of the tubing below the valve leading into the autoclave.

Example 4 Injection of Dry Catalyst in Slurry Phase Process (ZieglerLLDPE in Heptane Solvent)

12.2 g of dried glass beads (2 mm diameter) was added to the autoclaveto fill up the dead space at the bottom of the autoclave duringreaction. Dried heptane (120 ml) was then added to the autoclave

Triethylaluminium (0.75 mmol) was added to the autoclave followed by 20ml of hexene. The autoclave was heated to 85° C. and then hydrogen wasadded to 1 bar and ethylene added to 4 bar above the pressure of theheptane/hexene.

11.5 mg of a supported Ziegler polyethylene catalyst (catalyst C) wasmixed with 980 mg of solid diluent (TEA treated silica) in a nitrogenglove box and loaded into an injection capsule.

The injection capsule was transferred in to an injection chamber atatmospheric pressure via the use of a magnetised rod comprising anon-magnetic core section (plunger) and a magnetic outer section, whichare independently retractable. The injection chamber was pressurisedwith nitrogen to 10 bar above the autoclave pressure and the valve tothe autoclave was opened allowing the catalyst and TEA treated silicainto the autoclave. The pressure in the autoclave increased and theautoclave pressure was then controlled at this increased pressure byaddition of further reactant gas composition as required to maintainthis pressure. Activity was seen and the test was allowed to proceed for60 minutes at constant pressure and composition.

The product was removed at the end of the test by venting the reactantgases, cooling to 30° C. and opening a valve on the bottom of theautoclave. The autoclave was cleaned for the next test by washing with200 ml of heptane. All solid and liquid material from the autoclave wascollected.

On evaporating the heptane 4.9 g of LLDPE product was obtained. Theinjection capsule was removed from the injection chamber by venting thepressurised gas remaining in the injection chamber and using themagnetic rod to remove the injection capsule. Any residual solidmaterial in the injection chamber was removed by using a vacuum line.

On removal of the autoclave no significant deposits were seen on thewalls of the tubing below the valve leading into the autoclave.

1. An injection system for injecting material into a receiving vessel,said injection system comprising: i) an injection chamber provided withmeans to connect to the receiving vessel, and ii) an injection capsule,adapted to fit within the injection chamber, and comprising a reservoirfor the material and a valve, said injection system being adapted sothat opening of the valve causes material contained within the reservoirto be injected into the receiving vessel by action of a pressuredifferential between the injection chamber and the receiving vessel. 2.The injection system according to claim 1, wherein the injection capsulevalve is actuated by a pressure differential between the injectionchamber and the receiving vessel.
 3. The injection system according toclaim 2, wherein the injection capsule valve comprises a spring andplate assembly, wherein the plate is held in a closed position by thespring when there is no pressure differential.
 4. The injection systemaccording to claim 1, which further comprises at least partly automatedmeans for manipulation of the injection capsule.
 5. The injection systemaccording to claim 1, wherein the receiving vessel is a suitablereaction apparatus comprising a reactor and the material to be injectedis selected from catalyst materials, solvents, reactants, promoters,poisons, quench agents, scavengers, support particles or inert solids.6. The injection system according to claim 5, wherein the material to beinjected is a catalyst material.
 7. The injection system according toclaim 1, wherein the receiving vessel has a volume of between 10 ml and500 ml.
 8. The injection system according to claim 1, wherein theinjection chamber has a capacity of between 10 and 20% of the receivingvessel volume.
 9. The injection system according to claim 1, whichcomprises a plurality of injection chambers configured so as to delivermaterial to a plurality of receiving vessels.
 10. A process forinjecting materials into one or more receiving vessels using aninjection system as defined in claim 1, said process comprising: i)providing an injection capsule, containing the material to be injected,within an injection chamber, ii) pressurizing the injection chamber to apressure above that in the receiving vessel, and iii) opening a valve sothat material is injected into the receiving vessel.